Detection efficacy in 261 consecutive biochemical recurrent prostate cancer patients after radical prostatectomy using 18F-rhPSMA7 PET/CT imaging

Ziel/Aim:

¹⁸F-rhPSMA7 is a new theranostic PSMA-targeting agent which allow fast radiolabeling with ¹⁸F and radiometals. In addition, the tracer shows only minimal renal excretion. This retrospective analysis investigates the efficacy of ¹⁸F-rhPSMA7 PET/CT in biochemical recurrence (BCR).

Methodik/Methods:

261 consecutive patients with non-castrate BCR after radical prostatectomy underwent ¹⁸F-rhPSMA7 PET/CT imaging between June 2017 and March 201. The median PSA-level was 0.96 ng/ml (range: 0.01 – 400 ng/mL). Median injected activity was 336MBq median uptake time 76 min (range: 50 – 220 min). Images were reviewed by one nuclear medicine physician and all lesions suspicious for recurrent prostate cancer were noted. The detection rate of presumed recurrence sites was correlated with PSA-level, primary Gleason score, previous androgen deprivation therapy (ADT) and external beam radiation therapy (EBRT).

Ergebnisse/Results:

211 patients (80.8%) patients showed pathological findings in ¹⁸F-rhPSMA7 PET/CT. The detection rates were 71.2% (42/59), 86.3% (44/51), 85.7% (42/49) and 95.0% (76/80) at PSA-levels of 0.2-< 0.5 ng/ml, 0.5-< 1 ng/ml, 1-< 2 ng/ml and ≥2 ng/ml, respectively. ¹⁸F-rhPSMA7 PET/CT revealed local recurrence in 43.3% (113) patients. Lymph node metastases were present in the pelvis in 42.2% (110), in the retroperitoneum in 17.2% (45) and supradiaphragmatic location in 8.0% (21) patients. Bone and visceral metastases were detected in 20.7% (54) and 3.8% (10) patients. In 31.8% (7/22) patients with a PSA< 0.2 ng/ml suspicious lesions were present. Detection efficacy was not different between patients with prior EBRT (79.1% vs. 82.1%, p = 0.55), ADT within 6 months prior imaging (80.6% vs. 80.9%, p = 0.54) or primary histological differentiation (77.9% for Gleason Score ≤7 vs. 82.6% for Gleason Score ≥8, p = 0.38).

Schlussfolgerungen/Conclusions:

¹⁸F-rhPSMA7 PET/CT offers superb detection rates in BCR after radical prostatectomy with a trend towards higher efficacy compared to data published for ⁶⁸Ga-PSMA11.